Inverting Palladium–Phosphorus Lewis Pair Formation: Phosphonium Acting as Z‐Type Ligand

Abstract

Abstract Phosphorus‐based ligands are prototypical L‐type donors. Here, we introduce a Lewis acidic phosphonium cation that engages in unprecedented Z‐type coordination to palladium(0). The resulting Pd→P(V) interactions are structurally unique and stronger than conventional L‐type Pd─phosphine bonds, as revealed by NMR spectroscopy, x‐ray crystallography, and quantum chemical analyses (NBO, ETS‐NOCV, and QTAIM). It enables the formation of rare L 2 Z‐type Pd(0) complexes with distinctive optical and electronic properties. A notably mild P─C bond forming reaction suggests an overlooked role of Z‐type interactions for facilitating reductive elimination pathways.